1. Field of the Invention
This invention is related to the field of video processing and, more particularly, to the repositioning of images in a video display.
2. Description of the Related Art
Banner advertisements have become increasingly popular and important in television broadcasts, interactive TV applications, Internet Web browsers, and other multimedia applications. These advertisements allow the display of advertisements (ads) to attract viewers for commerce, information, and other purposes. In an interactive application, a banner ad typically occupies a portion of a display on top of a background image. Frequently, the background may be encoded as an MPEG I frame and the banner ad encoded as either a bitmap or an MPEG P frame.
Whether a banner ad is encoded as a bitmap or an MPEG P frame, various problems or limitations may be encountered. For example, bitmap banner ads may have limited color resolution due to restrictions inherent in the receiving device, such as a set-top box on-screen display (STB OSD). In addition, because bitmaps may be encoded as JPEG images, additional processing time may be required for decompression of the image. On the other hand, a banner ad encoded as an MPEG P frame may have a much higher color resolution and can generally be decoded by the MPEG hardware in the receiving device. However, placement of an ad on the screen may be more difficult when using a banner ad encoded as an MPEG P frame. In the absence of a mechanism which allows the STB to move the MPEG P frame banner ad to a desired location, the P frame must generally be retransmitted for each new display position. Further, because the MPEG decoder being used may require a valid MPEG stream in order to properly decode the stream, the choice of new location for an MPEG P frame banner ad may be limited. For example, the choice of new locations may be limited to locations on a macroblock (MB) boundary. In addition, moving a P frame to a new location may result in a change in bit position of the image data macroblocks. In such a case, bit shifting would generally be required which is a slow computation process.
Accordingly, a method and mechanism for repositioning a banner ad or other image in a data stream is desired.